<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>过滤器demo</title>
</head>
<body>
    {{ user.username }} - {{ user.username|length }} <br>
    {{ now|d_format }} <br>
    <!-- if 条件判断 -->
    {% if user.username == '燕双鹰' %}
        yes
    {% else %}
        no
    {% endif %}
    <!-- 循环控制 -->
</body>
</html>